Q355 steel is a low alloy, high-strength steel that is used in welded structures supporting stress and heavy loads. The Q references the yield point, while the number 355 indicates its yield strength. It also replaced Q345.
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Q355 is a high-strength low-alloy (HSLA) structural steel that contains phosphorus, sulfur, and microalloys, such as niobium, vanadium, titanium, and others. It is similar to Q345 in terms of chemical composition but has greater strength, toughness, and weldability.
Q355 steel has a tensile strength of 490-630 MPa, yield strength of 355 MPa, and elongation of 20%, making it suitable for use in various structural applications such as bridges, buildings, and machinery.
Some of the key features and properties of Q355 steel include:
- Superior strength: Q355 steel has higher tensile and yield strength than Q345 steel, making it ideal for use in high-stress structural applications.
- Good weldability: Q355 steel has good weldability, which makes it easy to fabricate and construct.
- Excellent toughness: Q355 steel exhibits excellent toughness, allowing it to withstand impact loads and resist deformation.
- Corrosion resistance: Q355 steel has good corrosion resistance, making it suitable for use in outdoor and marine environments.
- Affordable: Despite its superior properties, Q355 steel remains an affordable option for structural steel applications.
In summary, Q355 is a high-strength low-alloy structural steel with superior strength, good weldability, excellent toughness, and corrosion resistance. Its combination of properties makes it ideal for use in various structural applications where strength and durability are critical.
Q355 Equivalent Materials
Q355 can be replaced with equivalent materials, including A572 Grade 50 USA ASTM, Q355 China GB/T, and SPFC 590 Vietnam/Japanese JIS.
Characteristics of Q355
Q355 steel is a structural steel with a yield strength of 345 MPa and tensile strength of 450 MPa. It has terrific processing performance and compressive strength, which can be used to manufacture high-pressure gas pressure vessels containing less than 500 liters. Q355 also has a protective layer of rust resistance.
In addition to performance, Q355 has particular elements that prevent atmospheric corrosion. Since it is mild steel, it has a lower carbon content. If more carbon were added to the alloy, it would be reclassified as a cast iron.
Q355 is a newer Chinese steel grade that was designed to replace Q345. Its material density is 7.85 g/cm3 and possesses three quality levels, including Q355B, Q355C, and Q355D. It has great mechanical and hot and cold process properties. In contrast, it has better and more improved mechanical properties when compared to A36 ASTM steel.
Uses of Q355
Q355 steel has excellent mechanical properties, great weldability, and ample corrosion resistance. It can be utilized to manufacture and produce petroleum storage tanks, high-pressure vessels, boilers, ships, power stations, and many other high-load structural parts. Q355 is also widely used to make shipping containers, waste storage containers, weather containers, offshore containers, workshop containers, and toolboxes.
If you need steel that is created to stand up to the needs of construction and engineering components that provide excellent weldability and toughness, then Q355 may be a strong contender for your next project or job.
Q355 Physical Properties
| Physical Properties | Metric | US/Imperial |
|---|---|---|
| Density | 7.80 g/cc | 0.282 lb/in³ |
Mechanical properties Q355 steel
| Mechanical Properties | Metric | US/Imperial |
|---|---|---|
| Hardness, Brinell | 135 | 135 |
| Hardness, Rockwell B | 74 | 74 |
| Tensile Strength, Ultimate | 450 MPa | – |
| Tensile Strength, Yield | 345 MPa | – |
| Elongation at Break | 18 % | 18 % |
| 21 % | 21 % | |
| Bulk Modulus | 160 GPa | 23200 ksi |
| Shear Modulus | 80.0 GPa | 11600 ksi |
Component elements properties of Q355 steel
| Component Elements Properties | Metric | US/Imperial |
|---|---|---|
| Carbon, C | <= 0.23 % | <= 0.23 % |
| Iron, Fe | 0.98 | 0.98 |
| Manganese, Mn | 0.0135 | 0.0135 |
| Phosphorus, P | <= 0.040 % | <= 0.040 % |
| Silicon, Si | <= 0.40 % | <= 0.40 % |
| Sulfur, S | <= 0.050 % | <= 0.050 % |
| Silicon, Si | 0.15 – 0.40 % | 0.15 – 0.40 % |
| Sulfur, S | 0.0005 | 0.0005 |
The recent release of the new GB/T 1591-2018 standard has caused a lot of heated discussion. Will it form an interoperability with the European standard S355 series? Do you want to increase the amount of alloy added like the new national standard for rebar? Will not cause another alloy to turn 10 times the price?
As we all know, China’s steel production is the largest variety of rebar, followed by steel plate and sheet, and the largest percent of steel grade produced in the plate is Q235B, followed by Q345B. The biggest impact of the new GB/T 1591-2018 release is Q345B, because the output of other grades has little effect. According to what we said above, this change is in line with international standards. It can be told from the brand name, it is obviously in line with the European standard. Although it is based on ISO, in essence, in international trade, the S355JR steel plate production quantity is just like Q345B in China.
Q355B and EN10025
Why is it in line with the European standard?
Compared with the European standard EN10025, it is known that not only the brand names are similar, but also the chemical composition and mechanical properties are similar. For example, the first element C, the old national standard B level is less than or equal to 0.20, and the same as the European standard JR level. 0.24, of course, this is only one of the reasons. There are other aspects and performances that are almost identical to the European standard. In other words, the largest quantity of S355 in the conventional trade, the national standard and the European standard can already be equal.
Q355B Equivalent to S355
In terms of use: CEIBS has cooperated frequently in many fields in recent years. Many projects have come to purchase steel in China, and different standards will cause a lot of trouble. For example, the purchase of S355JR steel, most of which must be ordered from steel mill, and after the implementation of the new national standard The S355JR can be directly replaced with the Q355B. It can be said that the zero difference is docked, as long as the design strategy is slightly changed.
Future of Q355B Steel
Production: Although the demand for European standard products has gradually increased in recent years, due to different standard systems, different composition properties, production organization and its inconvenience, resulting in increased production costs, and after this change, S355JR and Q355B can almost judge each other. For the plate, it is basically to change the warranty book. Unlike the previous two brands, it is impossible to judge each other. If the S355 stream is single, it can only be used when it is available, and the price will be much lower. The Q345 series is also different from other aspects of the European change. The European standard order can only be regenerated, and the new national standard is not only the B-level intercommunication, but also several other levels, such as S355J0, J2, etc.